tuning fork frequency for vibration sense

Supramaximal stimulation was set to 120%, and five readings of each nerve were obtained and averaged. The filter settings for the sensory nerve conduction study were 10–2 kHz, sweep speed of 1–2 ms/division, and gain 1–5 mV/division. SNAPs were recorded orthodromically in the median nerve and antidromically in the sural and superficial peroneal nerves. The laboratory temperature was maintained at 22☌ ± 2☌. Before the placement of electrodes, the application sites were thoroughly cleaned with alcohol. For testing, the participant was seated comfortably in a chair with the hand and forearm resting on a pillow. The SNAPs of the median, sural, and superficial peroneal nerves were recorded using the Nicolet EDX EMG system (Natus Medical Incorporated, San Carlos, CA, USA). Participants of both the groups underwent timed VBS and JPS testing. The principal investigators who performed the tests for the study were blinded to the allotment of the groups. Normal participants who were willing to undergo nerve conduction studies and patients with nonneurological conditions and a normal nerve conduction study were included as the control group. Patients with acute neurological disorders, joint pathologies, disorders affecting consciousness, or awareness making them unable to cooperate for the examination and patients with skin lesions were excluded from the study. Between the periods of August 2017 and December 2017, consecutive patients who presented to the electrophysiology laboratory of the neuroscience department with a clinical diagnosis of a DSP were screened, and those patients who were between 18 and 80 years of age and electrophysiological studies confirmed DSP were included in the patient group. The study was approved by the Institutional Review Board and Ethics Committee.

This was a prospective study conducted in the neuroscience department of a tertiary care hospital in India. Hence, the objective in this study was to study the utility of joint position and timed VBS testing in the diagnosis of DSP. Timed VBS and JPS are integral parts of the sensory clinical examination, but there are limited data on its diagnostic utility.

Very few studies have explored the correlation between symptoms, examination findings, and electrophysiological results. Several studies have explored the role of the neurological examination in DSP, but these were mostly restricted to specific subgroups of patients such as diabetic polyneuropathy. However, there are limited data on its utility, and hence, there is a need for more research in this field. Despite advances in the available technology, neurological examination continues to play an important and pertinent role in the evaluation of patients with neurological illness. Patients with DSP restricted to small nerve fibers (A-delta fibers and unmyelinated C fibers), have minimal findings on the neurological examination, such as reduced pinprick or temperature sensation, preserved ankle jerks, and normal nerve conduction studies. On electrophysiological testing, the sensory nerve action potentials (SNAPs) are reduced or absent. Patients with DSP that predominantly affects the large sensory fibers (A-beta somatic fibers), present with tingling paresthesias and have impairment of joint position sense (JPS) and vibration sense (VBS) with absent ankle jerks. DSP commonly presents with distal symmetric sensory symptoms and rarely with imbalance while walking. Diabetes mellitus, impaired glucose tolerance, alcohol use, B12 deficiency, paraproteinemia, inherited conditions, and drugs contribute to form the more common causes of DSP. Distal sensory polyneuropathy (DSP) is a disease of the peripheral nerves and has a prevalence of 2.1%–8% in the general population.

Tuning fork frequency for vibration sense